/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.csp.sentinel;

import com.alibaba.csp.sentinel.node.ClusterNode;
import com.alibaba.csp.sentinel.node.DefaultNode;
import com.alibaba.csp.sentinel.node.EntranceNode;
import com.alibaba.csp.sentinel.slotchain.StringResourceWrapper;
import com.alibaba.csp.sentinel.util.VersionUtil;

/**
 * Universal constants of Sentinel.
 *
 * @author qinan.qn
 * @author youji.zj
 * @author jialiang.linjl
 * @author Eric Zhao
 */
public final class Constants {

  public static final String SENTINEL_VERSION = VersionUtil.getVersion("1.8.2");

  public final static int MAX_CONTEXT_NAME_SIZE = 2000;
  public final static int MAX_SLOT_CHAIN_SIZE = 6000;

  public final static String ROOT_ID = "machine-root";
  public final static String CONTEXT_DEFAULT_NAME = "sentinel_default_context";

  /**
   * A virtual resource identifier for total inbound statistics (since 1.5.0).
   */
  public final static String TOTAL_IN_RESOURCE_NAME = "__total_inbound_traffic__";

  /**
   * A virtual resource identifier for cpu usage statistics (since 1.6.1).
   */
  public final static String CPU_USAGE_RESOURCE_NAME = "__cpu_usage__";

  /**
   * A virtual resource identifier for system load statistics (since 1.6.1).
   */
  public final static String SYSTEM_LOAD_RESOURCE_NAME = "__system_load__";

  /**
   * Global ROOT statistic node that represents the universal parent node.
   */
  public final static DefaultNode ROOT = new EntranceNode(
      new StringResourceWrapper(ROOT_ID, EntryType.IN),
      new ClusterNode(ROOT_ID, ResourceTypeConstants.COMMON));

  /**
   * Global statistic node for inbound traffic. Usually used for {@code SystemRule} checking.
   */
  public final static ClusterNode ENTRY_NODE = new ClusterNode(TOTAL_IN_RESOURCE_NAME,
      ResourceTypeConstants.COMMON);

  /**
   * The global switch for Sentinel.
   */
  public static volatile boolean ON = true;

  /**
   * Order of default processor slots
   */
  public static final int ORDER_NODE_SELECTOR_SLOT = -10000;
  public static final int ORDER_CLUSTER_BUILDER_SLOT = -9000;
  public static final int ORDER_LOG_SLOT = -8000;
  public static final int ORDER_STATISTIC_SLOT = -7000;
  public static final int ORDER_AUTHORITY_SLOT = -6000;
  public static final int ORDER_SYSTEM_SLOT = -5000;
  public static final int ORDER_FLOW_SLOT = -2000;
  public static final int ORDER_DEGRADE_SLOT = -1000;

  private Constants() {
  }
}
